Nineteen-year-old Delmonte Johnson was fighting to stop gun violence in the city before his shooting death.

More than 20 people were shot over the weekend and last week in Chicago, including a 19-year-old gun violence activist. The shootings come after a brutal weekend last month in which at least 40 people were riddled with bullets.

Police reported two fatal shootings from Friday (Sept. 7) to Sunday (Sept. 9), the Chicago Sun-Times reported. Additionally, nineteen people were wounded in the crossfire. The incidents increased with each day: One person was struck on Friday, but eight and 12, respectively, were wounded on Saturday and Sunday.

The weekend violence came after activist Delmonte Johnson, 19, was shot and killed on the city’s South Side on Tuesday. The teen had been a part of the anti-bait truck giveaway—led by Chicago rapper Vic Mensa’s SaveMoneySaveLife Foundation and gun control organization Good Kids Mad City—that worked to stop cops from setting up “bait truck” stings to lure residents to steal.

He had volunteered with a group to stop violence on Chicago's streets. Last week, Delmonte Johnson died in that violence. https://t.co/6aHBiLpbHn

“I’m going to miss my baby,” his mother, Onique Walker, said about her son during a memorial Thursday, according to the Block Club Chicago. “Delmonte did his job. Servant well done. I did not know God was going to call you this early, but you know what? I can rest, I can sleep, I can laugh, because there weren’t any sad times.”

U.S. Rep Robin Kelly, who knew Johnson through Good Kids Mad City, which was formed after the Marjory Stoneman Douglas High School mass shooting in Parkland, Florida in February, posted a tribute video about Johnson on Friday.